In the semiconductor integral circuit manufacturing process for nano-electronics components and light detectors, an insulator layer is a critical element in preventing current leakage and keeping components isolated. In the prior art, technologies related to multi-quantum dots layers mainly focuses on developing germanium quantum dots on the silicon substrate, whereby the speed and efficiency of silicon-based optical electronic integral circuit (OEIC) devices can be enhanced. Such technologies are desirable in implementing LEDs (Light Emitting Diode) and light detectors, and effectively increase the performance of LEDs and light detectors. However, in the prior art, properties and behaviors of the germanium quantum dots developed on the silicon substrate have not been comprehensively researched. Accordingly, the performance of manufacturing process in field application based on such technologies has not been optimized.
The U.S. Pat. No. 5,354,707 titled “Method of Making Semiconductor Quantum Dot Light Emitting/Detecting Devices” is incorporated herein by reference. Refers to FIGS. 1A, 1B, 1C, and 1D, schematic sectional views at each formation step are described according to an embodiment of the aforementioned US patent. A silicon substrate 10 is illustrated in FIG. 1A. A micro epitaxial silicon substrate 15 is formed on the silicon substrate 10 in FIG. 1B. Then, at least one quantum dot 20 is formed on the micro epitaxial silicon substrate 15 in FIG. 1C. Another micro epitaxial silicon substrate 25 is formed on the micro epitaxial silicon substrate 15 where at least one quantum dot 20 is formed. The micro epitaxial silicon substrate 25 covers said at least one quantum dot 20. The formation and the application of said quantum dots 20 are limited in the prior art. Also, in the same prior art, details related to insulator layers are not mentioned.
In addition, drawbacks of the prior art are detailed as follows:    1. The prior art insulator layer is required to provide properties of dielectric materials;    2. The prior art can not provide protection over germanium quantum dot and micro epitaxial silicon;    3. The prior art has effects on the optical properties of the silicon-germanium elements.
According to the above, it is noted that the prior art fails to meet the requirements of the designs and the applications of the insulator layers. Therefore, the present invention provides solutions to overcome the drawbacks of the prior art, and optimize the application of the insulator layers.